HAVE YOU EVER WONDERED? Why some of us sneeze looking into a bright light

Are you part of the 20-30% of the population who start sneezing uncontrollably if they walk from a dark place to daylight? Then you have “photic sneeze reflex” or a “solar sneeze.” But why does it happen?

Professor Nicholas Langer from Zurich University has the most plausible answer. He examined 20 people, 10 with the trait and 10 without. They were connected to an EEG machine – which records brain activity – while exposed to bright light to measure their neural responses.

Prof Langer has two theories:

SORRY BUT I CAN’T ANSWER LETTERS PERSONALLY the first is that the brain’s visual system is more sensitive in solar sneezers and bright light triggers a response from the part of the brain which controls sneezing.

In his other theory a sneeze is triggered by the nose being irritated. The trigeminal nerve, the main one to the face and nose, lies alongside the optic nerve which sends visual information from the eye to the brain. So, when a sudden burst of light hits the optic nerve the signal can be sensed by the trigeminal nerve which mistakes it for the nose being irritated. Hence the sneeze.